Check engine light

[Stevoyayaya3]

So I have a 91 318is with the m42. When the car is on and stopped or parked the check engine light comes on, but as soon as I hit the gas it goes away. It drives fine with no problems. Any ideas guys? Thanks in advance

[vpilarrt]

Perform the stomp test.

1) Turn key to on but don't start the car
2) Press the gas pedal to the floor 5 times in quick succession
3) Count the check engine light flashes, these are 4 digit codes (with a time space between each digit) preceded by a long flash for which code this is (1st, 2nd, etc)
4) Search on this site for the explanation of codes

[Stevoyayaya3]

Awesome thanks. Ya I knew how to do that in my honda. But wondered how in my e30. So thanks

[jlevie]

You will probably find that the fault code will be 1222. Which is a Lambda fault and is caused by an apparent upset in the air fuel ratio. The common causes of that are intake leaks (a smoke test will find them) and/or an aged O2 sensor (replacement interval is every 100k).

[Stevoyayaya3]

Question does the code keep playing? Like I did it yesterday and the light flashed for like a minute. I wasn't sure. Like on a civic it will be long flashes(10) followed by short flashes(1) so three flashes followed by two short flashes would be 32. Maybe I'm just confused

[vpilarrt]

Is the key in the ON position and not the ACC? Should be 1 long flash (for the 1st code), a long (2-4 seconds) space, then short flashes with short spaces in between, then a long space followed by 2 long flashes (if a second code) or 1 long flash (if no second code but does repeat the 1st code), long space, then short flashes.